Method for plant-protection treatment by leaf absorption, using a combination between an active ingredient and a modified oil and novel combination for using said method

ABSTRACT

The subject of the invention is a method of plant-protection treatment by leaf absorption, characterized in that it uses a composition comprising at least one plant-protection active ingredient and at least one modified oil, a composition comprising at least one plant-protection active ingredient, at least one modified vegetable oil and at least one unmodified vegetable oil as well as an alkoxylated vegetable oil containing x% of glycerol.

[0001] The subject of the invention is a method for plant-protectiontreatment by leaf absorption, using a combination between an activeingredient and a modified oil and a novel combination for using saidmethod.

[0002] The use of oils is very widespread in the plant-protectiondomain; they are used either as formulation adjuvants, to increase theefficacy of the active substances, or as coformulants. Most of the oilsused are of petroleum origin and are formulated with surfactantscontaining aromatic nuclei such as ethoxylated alkylphenols. However,surfactants containing an aromatic nucleus are not rapidly biodegradableand damage thee ecosystems. For this reason, the use of rapeseed oil orof methyl esters of rapeseed oil is now growing; however, this oil isdifficult to formulate; it is a less satisfactory solvent for the activeingredient than oils of petroleum origin and, since it does not possessintrinsic surfactant properties, it has to be used in combination withsurfactants containing an aromatic nucleus. In the international patentapplication, published under the number WO 96/22109, ethoxylated fattyacid esters are described as self-emulsifiable compounds which can beused in formulations of plant-protection active ingredients such asethephon or chlorpropham; however, nothing is written or suggested onthe activity of the compositions resulting from this combination.However, the penetration of the plant-protection active ingredient intothe plant occurs either at the level of the leaves, through leafabsorption, or at the level of the roots, through radicular absorption;it is known furthermore that leaf absorption of an active ingredient isoften difficult; it is observed that after seventy-two hours, up to 95%of the active ingredient is still not absorbed by the plant. A period ofrain following the treatment of a crop therefore risks inducingpollution of the site, while a period of sunshine can cause thedegradation of the, active ingredient. The work by C. Gauvrit and F.Cabanne [Pesticide Science, 37, 147-153 (1993)] has recently made itpossible to demonstrate that the increase in the efficacy of herbicidesin the presence of oils is attributed to a spreading of the dropletsdeposited at the surface of the leaves, and to a better leaf penetrationof the herbicidal active ingredient. However, these effects, for theoils used up until now, only manifest themselves markedly on plantscontaining crystalline cuticular waxes, such as for example theGramineae, whereas on the amorphous cuticular waxes of dicotyledons, theeffects of these oils are more modest [C. Urvoy, M. Pollacsek and C.Gauvrit, Weed Research, 32, 375-383 (1992); I. Serre, F. Cabanne and C.Gauvrit, Medelingen van de Facultelt LandbouwwentenschappenRijksuniversiteit Gent 58/3a, 795-802 (1993)]. Starting from thehypothesis that oils can increase the leaf penetration of the productsby acting on the availability of the active substances at the surface ofthe leaf and on the mobility of the substances in the diffusion barrierwhich the plant cuticle constitutes [I. Serre, University of Grenoblethesis (1996); I. Serre, F. Cabanne and C. Gauvrit, British CropProtection Conference 7B-3, 807-812 (1996)], the applicant has thussought to develop a method of plant-protection treatment by leafabsorption which allows, in a short time, a high level of absorption ofthe active ingredient by the plant while limiting the nuisances to theecosystems, by the use of a composition which is sufficiently effectiveas solvent for the active ingredient and sufficiently stable over timeto be marketable.

[0003] The subject of the invention is a method of plant-protectiontreatment by leaf absorption, characterized in that it uses acomposition comprising at least one plant-protection active ingredientand at least one modified oil.

[0004] The expression modified oil denotes either alkoxylated or elseand in particular ethoxylated and/or propoxylated oils, or alkoxylatedalkyl esters of the oils and in particular ethoxylated and/orpropoxylated methyl, ethyl, linear or branched propyl, or linear orbranched butyl esters of said oils. According to a specific aspect ofthe present invention, the ethoxylated oils or the ethoxylated alkylesters of vegetable oils each have an ethylene oxide number, called inthe text which follows EO value, of between 1 and 50.

[0005] The modified oils used in the context of the present inventionmay be. of mineral, plant or animal origin. Among the modified oils ofmineral origin which may be used in the method as defined above, thereare in particular the modified oils of petroleum origin; among themodified oils of animal origin which may be used in the method asdefined above, there is in particular modified tallow oil; among themodified oils of plant origin which may be used in the method as definedabove, there are, for example, modified sunflower, linseed, castor,soybean, corn, groundnut, copra, olive, palm, hydrogenated palm orrapeseed oils.

[0006] The expression at least one modified oil indicates that thecomposition used in the method which is the subject of the presentinvention may comprise either a single modified oil or a mixture ofseveral modified oils; in the latter case, this may include a mixture ofmodified oils of the same origin or a mixture of modified oils ofdifferent origins.

[0007] The expression plant-protection treatment is understood to meanin the context of the present invention preferably a fungicidal,insecticidal or herbicidal treatment.

[0008] According to a specific variant of the method as defined above,the plant-protection composition used contains at least one modifiedvegetable oil, alone or in the form of a mixture with one or moremodified oils of the same origin or of different origins.

[0009] According to another specific variant of the method as definedabove, the plant-protection composition used contains, in addition, anunmodified vegetable oil or a mixture of unmodified vegetable oils. Theexpression unmodified vegetable oil is understood to mean vegetable oilsor their alkyl esters, such as for example the methyl, ethyl, linear orbranched propyl, or linear or branched butyl esters.

[0010] According to another aspect of the present invention, its subjectis a composition comprising at least one plant-protection activeingredient, at least one modified vegetable oil and at least oneunmodified oil.

[0011] The unmodified oil contained in the above composition is an oilof plant, animal or mineral origin. The expression unmodified oil isunderstood to mean oils or their alkyl esters, such as for example themethyl, ethyl, linear or branched propyl, or linear or branched butylesters.

[0012] The subject of the invention is more particularly a compositionas defined above in which the oil or the mixture of unmodified oils isof plant origin and is preferably chosen from sunflower, linseed,castor, soybean, corn, groundnut, copra, olive, palm, hydrogenated palmor rapeseed oils.

[0013] The expression modified vegetable oil denotes either alkoxylatedvegetable oils and in particular ethoxylated and/or propoxylatedvegetable oils, or alkoxylated alkyl esters of the oils and inparticular ethoxylated and/or propoxylated methyl, ethyl, linear orbranched propyl, or linear or branched butyl esters.

[0014] According to a specific aspect of the present invention, theethoxylated oils or the ethoxylated alkyl esters of vegetable oils eachhave an ethylene oxide number, called in the text which follows EOvalue, of between 1 and 50.

[0015] The subject of the invention is more particularly a compositionas defined above which comprises at least one ethoxylated methyl esterof a vegetable oil having an EO value of between 1 and 4, moreparticularly of equal to 1 or 2 and at least one unmodified oil.According to a most specific aspect of the present invention, thecomposition comprises an ethoxylated methyl ester of a vegetable oil andthe same vegetable oil which is unmodified. The ester of ethoxylatedvegetable oil/unmodified vegetable oil weight ratio is in generalbetween 1/50 and 50/1 and more particularly between 1/9 and 9/1.

[0016] The subject of the invention is also more particularly acomposition comprising at least one plant-protection active ingredient,at least one ethoxylated vegetable oil having an EO value of between 10and 40 and more particularly greater than or equal to 15 and less thanor equal to 30, and at least one unmodified oil. According to a mostspecific aspect of the present invention, the composition as definedabove comprises an ethoxylated vegetable oil, and the same vegetable oilwhich is unmodified. The ethoxylated vegetable oil/unmodified oil weightratio is generally between 1/50 and 50/1 and more particularly between1/9 and 9/1.

[0017] To improve its stability in the cold, the alkoxylated oil may beprepared by incorporating, before its alkoxylation, from 1 to 10% byweight of glycerol. This problem may also be solved by combining, in thesame composition, an alkoxylated vegetable oil as defined above and analkoxylated alkyl ester of vegetable oil, as defined above, and moreparticularly an ethoxylated and/or propoxylated methyl, ethyl, linear orbranched propyl, or linear or branched butyl ester of a vegetable oiland, more particularly, by combining an ethoxylated vegetable oil havingan EO value of between 10 and 40 and preferably greater than or equal to15 and less than or equal to 30, with an ethoxylated methyl ester of avegetable oil having an EO value of between 1 and 4, preferably equal to1 or 2.

[0018] According to a final aspect of the present invention, its subjectis a modified vegetable oil capable of being obtained by mixing, in thepresence of a basic catalyst, from 1 to 10 parts of glycerol per 100parts of an unmodified vegetable oil chosen from sunflower oil, linseedoil, castor oil, soybean oil, corn oil, groundnut oil, copra oil, oliveoil, palm oil or hydrogenated palm oil, and then alkoxylating theresulting mixture; and more particularly a modified vegetable oil asdefined above for which the average degree of ethoxylation isapproximately greater than or equal to 10, preferably greater than orequal to 15, and less than or equal to 40, and preferably less than orequal to 30. The following examples illustrate the invention without,however, limiting it.

EXAMPLE 1 Preparation of Modified Oils

[0019] A) Preparation of Ethoxylated Methyl Esters of Rapeseed Oil

[0020] Starting with the methyl ester of rapeseed oil, by reacting for45 minutes approximately at 180° C., with the quantity of ethylene oxidenecessary for obtaining the desired molar ratio, at a pressure of 4.5bar, in the presence of a basic catalyst, and then cooling andneutralizing the catalyst, the following ethoxylated methyl esters ofrapeseed oils were prepared: COMPOUND ETHOXYLATION VALUE 1 0 2 1 3 2 4 35 4 6 6 7 8

[0021] B) Preparation of Ethoxylated Rapeseed Oils Containing 2%Glycerol

[0022] Using the ethoxylation method described in the precedingparagraph, in the presence of 2% by weight of glycerol, on rapeseed oil,the following ethoxylated rapeseed oils containing 2% of glycerol areobtained: COMPOUND ETHOXYLATION VALUE  8 15  9 20 10 25

[0023] C) Preparation of Ethoxylated Rapeseed Oils x% of Glycerol

[0024] Using the ethoxylation method described in the precedingparagraph, on rapeseed oil in the presence of variable quantities ofglycerol, the following ethoxylated rapeseed oils containing x% ofglycerol are obtained: COMPOUND ETHOXYLATION VALUE % GLYCEROL 11 20 1 1220 2 13 20 5 14 20 10  15  0 2 16  3 2 17  6 2 18 10 2 19 20 2 20 30 221 40 2

[0025] D) Preparation of Ethoxylated Linseed Oils Containing 2% ofGlycerol

[0026] Using the ethoxylation method described in paragraph A in thepresence of 2% by weight of glycerol, on linseed oil, the followingethoxylated linseed oils containing 2% of glycerol are obtained:COMPOUND ETHOXYLATION VALUE % GLYCEROL 22  0 2 23 10 2 24 20 2 25 30 226 40 2

[0027] E) Preparation of Ethoxylated Methyl Esters of Sunflower Oil

[0028] Using the ethoxylation method described in the precedingparagraph, on the methyl ester of sunflower oil, the followingethoxylated methyl esters of sunflower oil are obtained: COMPOUNDETHOXYLATION VALUE 27 2

[0029] F) Preparation of Ethoxylated Sunflower Oils Containing 4% ofGlycerol

[0030] Using the ethoxylation method described in paragraph A in thepresence of 4% by weight of glycerol, on sunflower oil, the followingethoxylated sunflower oils containing 4% of glycerol are obtained:COMPOUND ETHOXYLATION VALUE % GLYCEROL 28  0 4 29  1 4 30  3 4 31  6 432 10 4 33 20 4 34 30 4 35 40 4

[0031] G) Preparation of Ethoxylated Corn Oils Containing 2% of Glycerol

[0032] Using the ethoxylation method described in paragraph A in thepresence of 2% by weight of glycerol, on corn oil, the followingethoxylated corn oils containing 2% of glycerol are obtained: COMPOUNDETHOXYLATION VALUE % GLYCEROL 36  0 2 37 10 2 38 20 2 39 30 2 40 40 2

EXAMPLE 2 Physicochemical Evaluation of the Modified Oils

[0033] The solubilities in water and in an aqueous solution containing10% by weight of sodium lauryl ether sulfate, the emulsifying power, theself-emulsifying power and the wetting power were evaluated according toconventional methods, for each of the modified oils prepared. The resultis that compounds 2, 3, 8 to 13, 19 to 21, 24 to 27, 33 to 35 and 38 to40 are more appropriate than the others for carrying out the methodwhich is the subject of the present invention.

EXAMPLE 3 Study of the Capacity of the Modified Vegetable Oils toStimulate Leaf Penetration of a Plant-protection Active Ingredient

[0034] A) Phenmedipham compositions

[0035] The penetration into barley (Hordeum vulgare) leaves, ofphenmedipham, which [lacuna] a herbicide having a high melting point(greater than 100° C.) called 3-[(methoxycarbonyl) amino] phenyl(3-methylphenyl)-carbamate, alone or in combination with modified oils,was compared according to the following procedure: The carbon-14 labeledphenmedipham is dissolved (42 bq μl⁻¹), in the presence or in theabsence of modified vegetable oils (about 10 nM), in acetone, a solventwhich does not affect the cuticular waxes and which, by evaporatingrapidly, does not interfere with the penetration process. Ten drops areapplied to the adaxial surface of the first leaf. After 0, 4, 6, 24 or72 hours, the product which has not penetrated is washed with 0.5 ml ofacetone and the radioactivity measured by liquid scintillation. Theradioactivity present in the treated leaf in the rest of the plant isdetermined in the carbon dioxide obtained after burning the tissue. Theresults, expressed as a percentage of the active ingredient which haspenetrated into the leaf, are presented in the following table: LEAFPENETRATION AT: COMPOSITION 06 HOURS 24 HOURS 72 HOURS PHENMEDIPHAMALONE <10% PHENMEDIPHAM + ˜45% ˜80% ˜80% COMPOUND 36 PHENMEDIPHAM + ˜40%˜60% ˜70% COMPOUND 37 PHENMEDIPHAM + ˜25% ˜50% ˜55% COMPOUND 38PHENMEDIPHAM + ˜20% ˜40% ˜55% COMPOUND 39 PHENMEDIPHAM + ˜10% ˜30% ˜40%COMPOUND 40 PHENMEDIPHAM + ˜75% >80% >80% COMPOUND 22 PHENMEDIPHAM +˜40% ˜70% ˜75% COMPOUND 23 PHENMEDIPHAM + ˜20% ˜50% ˜55% COMPOUND 24PHENMEDIPHAM + ˜20% ˜50% ˜50% COMPOUND 25 PHENMEDIPHAM + ˜10% ˜40% ˜35%COMPOUND 26 PHENMEDIPHAM + ˜65% ˜80% >90% COMPOUND 15 PHENMEDIPHAM +˜60% ˜75% ˜80% COMPOUND 16 PHENMEDIPHAM + ˜55% ˜70% ˜80% COMPOUND 17PHENMEDIPHAM + ˜50% ˜70% ˜80% COMPOUND 18 PHENMEDIPHAM + ˜25% ˜55% ˜70%COMPOUND 19 PHENMEDIPHAM + ˜25% ˜55% ˜75% COMPOUND 20 PHENMEDIPHAM +˜15% ˜45% ˜65% COMPOUND 21 PHENMEDIPHAM + ˜80% ˜75% ˜75% COMPOUND 28PHENMEDIPHAM + ˜80% ˜85% ˜90% COMPOUND 29 PHENMEDIPHAM + ˜80% ˜85% ˜90%COMPOUND 30 PHENMEDIPHAM + ˜60% ˜65% ˜60% COMPOUND 31 PHENMEDIPHAM +˜60% ˜75% ˜90% COMPOUND 32 PHENMEDIPHAM + ˜35% ˜55% ˜60% COMPOUND 33PHENMEDIPHAM + ˜35% ˜60% ˜65% COMPOUND 34 PHENMEDIPHAM + ˜30% ˜50% ˜60%COMPOUND 35 PHENMEDIPHAM + ˜50% ˜75% ˜80% COMPOUND 11 PHENMEDIPHAM +˜50% ˜75% ˜75% COMPOUND 12 PHENMEDIPHAM + ˜50% ˜75% ˜70% COMPOUND 13PHENMEDIPHAM + ˜50% ˜75% ˜75% COMPOUND 14 PHENMEDIPHAM + >80% ˜85% ˜90%COMPOUND 27 PHENMEDIPHAM + ˜95% ˜90% ˜90% COMPOUND 1 PHENMEDIPHAM + ˜90%˜90% ˜90% COMPOUND 2 PHENMEDIPHAM + ˜85% ˜90% ˜90% COMPOUND 3PHENMEDIPHAM + ˜80% ˜85% ˜90% COMPOUND 4 PHENMEDIPHAM + ˜80% ˜85% ˜90%COMPOUND 5 PHENMEDIPHAM + ˜75% ˜75% ˜75% COMPOUND 6 PHENMEDIPHAM + ˜65%˜75% ˜80% COMPOUND 7

[0036] B) 2,4-D Compositions

[0037] The penetration into barley (Hordeum vulgare) leaves, of 2,4-D or(2,4-dichlorophenoxy) acetic acid, which is a herbicide with a highlydissociated carboxylic acid function, alone or in combination withmodified oils, was compared according to the procedure described in thepreceding paragraph.

[0038] The following results are obtained: LEAF PENETRATION AT:COMPOSITION 06 HOURS 24 HOURS 72 HOURS 2,4-D ALONE —   10%   15% 2,4-D +COMPOUND 15 — >70% >80% 2,4-D + COMPOUND 16 — >70% >80% 2,4-D + COMPOUND17 — >70% >80% 2,4-D + COMPOUND 18 >70% >80% 2,4-D + COMPOUND19 >70% >80% 2,4-D + COMPOUND 20 >70% >80% 2,4-D + COMPOUND 21 >70% >80%

[0039] These results demonstrate the benefit of combining one or moremodified oils with an active ingredient which is anionic and/or has ahigh melting point (>100°C.), for a plant-protection treatment by leafabsorption.

What is claimed:
 1. Method of plant-production treatment by leafabsorption, characterized in that it uses a composition comprising atleast one plant-protection active ingredient and at least one modifiedoil.
 2. Method as defined in claim 1, in which the composition usedcomprises at least one modified oil chosen either from ethoxylatedand/or propoxylated oils, or from ethoxylated and/or propoxylatedmethyl, ethyl, linear or branched propyl, or linear or branched butylesters of oils.
 3. Method as defined in claim 1, in which thecomposition used comprises at least one ethoxylated oil, or at least oneethoxylated methyl, ethyl, linear or branched propyl, or linear orbranched butyl ester of oils, each having an EO value of between 1 and50.
 4. Method as defined in claim 1, in which the composition usedcomprises at least one or more modified oils of plant origin chosen frommodified sunflower, linseed, castor, soybean, corn, groundnut, copra,olive, palm, hydrogenated palm or rapeseed oils.
 5. Method as defined inclaim 4, in which the composition used contains, in addition, avegetable oil or a mixture of vegetable oils.
 6. Method as defined inclaim 1, in which the active ingredient is a herbicide.
 7. Compositioncomprising at least one plant-protection active ingredient, at least onemodified vegetable oil and at least one unmodified oil.
 8. Compositionas defined in claim 7, in which the unmodified oil or the mixture ofunmodified oils is of plant origin and is preferably chosen fromsunflower, linseed, castor, soybean, corn, groundnut, copra, olive,palm, hydrogenated palm or rapeseed oils.
 9. Composition as defined inclaim 7, in which the modified vegetable oil or the mixture of modifiedvegetable oils is chosen from ethoxylated and/or propoxylated vegetableoils, or from ethoxylated and/or propoxylated methyl, ethyl, linear orbranched propyl, or linear or branched butyl esters of vegetable oils.10. Composition as defined in claim 9, in which the modified vegetableoil is an ethoxylated methyl ester having an EO value of between 1 and4, more particularly equal to 1 or
 2. 11. Composition as defined inclaim 10, in which the modified vegetable oil is at least oneethoxylated vegetable oil having an EO value of between 10 and 40 andmore particularly greater than or equal to 15 and less than or equal to30.
 12. Composition as defined in claim 7, in which the modifiedvegetable oil and the unmodified vegetable oil are derived from the sameplant.
 13. Composition as defined in claim 7, in which the modifiedvegetable oil/unmodified oil weight ratio is between 1/50 and 50/1 andmore particularly between 1/9 and 9/1.
 14. Composition as defined inclaim 7, in which the modified oils are capable of being obtained bymixing, in the presence of a basic catalyst, from 1 to 10 parts ofglycerol per 100 parts of unmodified oils, and then alkoxylating theresulting mixture.
 15. Composition as defined in claim 7, comprising atleast one alkoxylated vegetable oil and at least one alkoxylated alkylester of a vegetable oil, more particularly comprising an ethoxylatedand/or propoxylated methyl, ethyl, linear or branched propyl, or linearor branched butyl ester of a vegetable oil and one ethoxylated and/orpropoxylated vegetable oil, and most particularly comprising anethoxylated methyl ester of a vegetable oil having an EO value ofbetween 1 and 4, and preferably equal to 1 or 2 and an ethoxylatedvegetable oil having an EO value of between 10 and 40 and preferablygreater than or equal to 15 and less than or equal 30.